Document the maximum numbers of characters needed in the buffer

Author: lysnikolaou

Doc/c-api/unicode.rst

@@ -310,7 +310,8 @@ These APIs can be used for fast direct character conversions:
 .. c:function:: Py_ssize_t PyUnicode_ToLower(Py_UCS4 ch, Py_UCS4 *buffer, int size)
 
    Convert *ch* to lower case, store result in *buffer*, which should be
-   able to hold as many characters needed for *ch* to be lower cased, and
+   able to hold as many characters needed for *ch* to be lower cased
+   (e.g. a maximum of two character for Unicode 16.0), and
    return the number of characters stored. Passing a ``NULL`` buffer returns
    the buffer size needed. If at some point a buffer overflow is detected,
    an :exc:`ValueError` is raised and ``-1`` is returned.
@@ -321,7 +322,8 @@ These APIs can be used for fast direct character conversions:
 .. c:function:: Py_ssize_t PyUnicode_ToUpper(Py_UCS4 ch, Py_UCS4 *buffer, int size)
 
    Convert *ch* to upper case, store result in *buffer*, which should be
-   able to hold as many characters needed for *ch* to be upper cased, and
+   able to hold as many characters needed for *ch* to be upper cased
+   (e.g. a maximum of three character for Unicode 16.0), and
    return the number of characters stored. Passing a ``NULL`` buffer returns
    the buffer size needed. If at some point a buffer overflow is detected,
    an :exc:`ValueError` is raised and ``-1`` is returned.
@@ -332,7 +334,8 @@ These APIs can be used for fast direct character conversions:
 .. c:function:: Py_ssize_t PyUnicode_ToTitle(Py_UCS4 ch, Py_UCS4 *buffer, int size)
 
    Convert *ch* to title case, store result in *buffer*, which should be
-   able to hold as many characters needed for *ch* to be title cased, and
+   able to hold as many characters needed for *ch* to be title cased
+   (e.g. a maximum of three character for Unicode 16.0), and
    return the number of characters stored. Passing a ``NULL`` buffer returns
    the buffer size needed. If at some point a buffer overflow is detected,
    an :exc:`ValueError` is raised and ``-1`` is returned.
@@ -343,7 +346,8 @@ These APIs can be used for fast direct character conversions:
 .. c:function:: Py_ssize_t PyUnicode_ToFolded(Py_UCS4 ch, Py_UCS4 *buffer, int size)
 
    Foldcase *ch*, store result in *buffer*, which should be
-   able to hold as many characters needed for *ch* to be foldcased, and
+   able to hold as many characters needed for *ch* to be foldcased
+   (e.g. a maximum of three character for Unicode 16.0), and
    return the number of characters stored. Passing a ``NULL`` buffer returns
    the buffer size needed. If at some point a buffer overflow is detected,
    an :exc:`ValueError` is raised and ``-1`` is returned.